Engineered Blood Vessels Shift After Surgery, Model Shows Hemodynamic Cost

Researchers who compared preoperative designs with postoperative anatomies in four porcine aortas found that the grafts could shift by up to 6.9 millimeters and rotate by as much as 38 degrees after implantation. Those deviations were enough to change predicted blood-flow behavior substantially: the discrepancy between predicted and actual pressure drop reached 2.5 millimeters of mercury, a 50 percent difference, while time-averaged wall shear stress diverged by 7.2 pascals, or 72 percent, from what the design stage anticipated.

The work, published in Annals of Biomedical Engineering, combined an in vivo experiment with computational modeling to answer a question that has lingered as engineered vessels move toward clinical use: how much does imperfect placement actually matter for hemodynamics? The team first measured the mismatch between designed and postoperative geometries in the four pig aortas. They then used those measured discrepancies to inform a virtual implantation study in which graft location, orientation, and size were systematically varied to see how each factor altered the final aortic shape and the blood flow within it.

Two computational tools anchored the analysis. Finite element modeling simulated the anastomosis, the surgical joining of the graft to the native aorta, predicting how the vessel wall would deform once sutures pulled the engineered conduit into place. Computational fluid dynamics then extracted the key hemodynamic metrics from both the virtual implantations and the actual postoperative anatomies. One notable methodological gain emerged from this pairing: adding virtual anastomosis simulations improved aortic shape predictions by 27.5 percent, suggesting that modeling the mechanical act of suturing, not just the final intended geometry, brings predictions closer to what surgeons see on postoperative imaging.

The virtual experiments identified which degrees of freedom matter most. Peak systolic pressure drop proved most sensitive to translation in the inferior-superior direction, meaning the graft sitting slightly too high or too low, and to rotation about the anterior-posterior axis. Size mismatch told a different story: it had a greater impact on time-averaged wall shear stress, changing it by as much as 85 percent, than on peak systolic pressure drop, which shifted by only 23 percent.

The in vivo portion of the study gave the modeling its grounding. Rather than assuming arbitrary displacement ranges, the researchers anchored their virtual scenarios to the deviations actually observed in the four porcine aortas after implantation. That anchoring matters because it turns the simulation study into a bounded sensitivity analysis: the reported sensitivities describe the consequences of displacements and size errors within the ranges that real surgery produced, not extremes that may never occur in practice. The measured ceiling of 6.9 millimeters of translation and 38 degrees of rotation therefore serves both as a description of current surgical variability and as the envelope within which the hemodynamic consequences were quantified.

For the field of vascular reconstruction, the results carry a practical message. Tissue-engineered vascular grafts have shown promise in advancing vascular reconstructions, but precise in vivo implantation remains challenging, and it was unclear how deviations in location and size translate into altered hemodynamics.

Limitations remain. The in vivo comparison rested on four porcine aortas, so the displacement ranges and hemodynamic discrepancies reported here describe that cohort, and the authors frame their conclusions as highlighting sensitivity rather than establishing clinical thresholds. The hemodynamic metrics were obtained through computational fluid dynamics on virtual and postoperative geometries, which depends on the fidelity of the reconstructed anatomies.

Subject of Research: Hemodynamic effects of displacement and size mismatch in tissue-engineered vascular graft implantation, studied in pigs and by computational modeling

Article Title: Assessing Hemodynamic Impact of Tissue-Engineered Vascular Graft Displacement: Combining Postoperative In Vivo Results and Computational Modeling to Improve Surgical Planning

Article References: Aslan, S., Chen, E., Mese-Jones, M., Contento, J., Hayashi, H., Kawaji, K., Huddle, J., Johnson, J., Loke, Y.-H., Fuge, M., Olivieri, L., Nguyen, T. D., Hibino, N., & Krieger, A. (2026). Assessing Hemodynamic Impact of Tissue-Engineered Vascular Graft Displacement: Combining Postoperative In Vivo Results and Computational Modeling to Improve Surgical Planning. Annals of Biomedical Engineering. https://doi.org/10.1007/s10439-026-04424-y

Image Credits: AI Generated

DOI: 10.1007/s10439-026-04424-y

Keywords: tissue-engineered vascular grafts, hemodynamics, computational fluid dynamics, finite element modeling, porcine aorta, graft displacement, wall shear stress, pressure drop, surgical planning, anastomosis, vascular reconstruction, Assessing